The subject matter disclosed herein relates generally to transmission line circuitry, and more particularly to feed networks for antennas.
Various types of feed networks are used to feed radio frequency (RF) energy between one or more antennas and associated processing systems, such as transmitters, receivers, and/or transceivers. For example, a feed network may convert RF waves received by an antenna into RF electrical signals and deliver the RF electrical signals to the processing system, and/or vice versa. Known feed networks may include one or more various components for controlling the amplitude and phase of RF power at the antenna(s), and may include RF devices such as baluns, hybrid couplers, delay lines, phase shifters, and/or the like.
Known feed networks are not without disadvantages. For example, a plurality of antennas are often grouped together in an array. Each antenna typically includes a dedicated feed network that serves that particular antenna. Accordingly, the antenna array typically includes a plurality of antenna and feed network pairs. But, there may be a limited amount of space for containing the antenna and feed network pairs, which may limit the minimum spacing between antennas in an array. For example, the length, width, and/or a similar dimension (e.g., a diameter and/or the like) of at least some known feed networks may limit the minimum spacing between antennas in an array. Electronically-steerable antenna arrays exhibit grating lobes in at least some angular regions for antenna element spacings greater than one-half of a wavelength at the frequency of operation. Thus, the minimum spacing between antenna elements can determine the maximum operating frequency of an antenna array.
Another disadvantage of at least some known feed networks is bandwidth. Specifically, the operational frequency band of at least some known feed networks may be too narrow to enable the associated antenna to communicate with one or more devices.
Another disadvantage of at least some known feed networks is fabrication cost. Specifically, at least some known feed networks require manual assembly, lumped-element RF devices, and/or a high layer count (e.g., greater than four) printed circuit(s) with single or multiple lamination cycles.